I am trying to put together a model rocket launcher for my son and am having issues with wiring. He wanted it to look "cool" so I have two SPST switches that light when powered, and a single SPST push switch. All are in series, and powered by two 9v batteries in series. One switch powers, then the next arms, and finally the push button is supposed to fire. What happens in reality is when the circuit is closed by the push button the lighted switches turn off and power is lost. I've included a diagram. Do I need resistors after grounds on the switches to limit power flow? I've looked at several designs online and mine seems to be the same.
Examples:
http://www.instructables.com/id/remote-model-rocket-ignitor/
http://www.instructables.com/id/Model-Rocket-Launch-Controller/
Best Answer
two possibilities . your circuit looks fine . have you connected to the correct terminals on the switches ? Or it could be that your battery is too small . In that case the igniter would draw so much current that the battery voltage falls too low to ignite or light the LEDs. I would monitor the battery voltage with a multimeter whilst operating the switches. I assume that the LEDs have an internal resistor . If they do not you will need to add series resistors of around 1K.